[lwip-devel] igmp implementation

[Bill Florac]

I'm attempting to implement igmp off the latest build.  I see that I need to 
implement at igmp_mac_filter function.  My plan is to implement this in the 
ethernetif.c module.  It would be assigned to the netif structure in the 
low_level_init() function.  The function would then make the correct calls to 
the device driver (Atmel AT91 EMAC) to set or clear the correct hash key.
 
As we leave a group we need to make sure that know another joined group address 
resolves to the same hash key. If so, we don't want to clear the key. There are 
a number of ways to resolve this.  We could keep a some sort of reference count 
or we can test the entire group list as we leave a group. If we do a test, 
either the igmp_mac_filter() would need to have the list of groups or the 
calling function igmp_leavegroup() would have to have access to the hashkey() 
function (making it HW dependent).
 
Any thoughts how to best/better handle this?
 
Bill